Oil Pressure on New Rebuild - Page 3 - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > General Technical Discussions > Engines & Drivetrain > Oil Pressure on New Rebuild

Introducing MONSTALINER™ UV Permanent DIY Roll On Bed LineSavvy/Currie Aluminum Control ArmsRockridge 4WD IS Taking Zone Offroad Suspension Lift Kits

Reply
Unread 08-31-2013, 07:53 AM   #31
laybackman
Bikini Bridge Inspector
 
laybackman's Avatar
1995 YJ Wrangler 
 
Join Date: Dec 2002
Location: Massachusetts
Posts: 6,274
Quote:
Originally Posted by BIGBADWOLF View Post
The pump itself when it runs dry because most of the oil is being pumped to the top of the engine faster than it can drain back to the sump.
And that is why high volume oil pumps need larger base pans. Putting a high volume oil pump into an engine that has worn bearings is a waste of $$$. It is cheaper and just as effective to just use heavier oil.

Bottom line is once your clearances are too large it is time to at least swap out the worn main and connecting rod bearings along with a new stock oil pump.

__________________
"Taking care of our veterans is a cost of war. If you can spend six trillion dollars sending people to war, you can spend a few billion dollars taking care of them when they come home"
Sen. Bernie Sanders (I-Vt.)

If what doesn't kill you, makes you stronger, I should be able to bench press a Grand Cherokee by now!
laybackman is offline   Reply With Quote Quick reply to this message
Unread 08-31-2013, 08:41 AM   #32
uberxj92
Registered User
1992 XJ Cherokee 
 
Join Date: Oct 2012
Location: umatilla, florida
Posts: 1,962
Quote:
Originally Posted by cruiser54 View Post
Engine oil pressure has NOTHING to do with seal life.

4.0s did indeed use HV oil pumps in some applications for the military.

And what other important parts can be damaged by higher oil volume?
So you're telling me that seals can withstand infinite amounts of pressure for infinite amounts of time?
Did you install the larger capacity pan?
__________________
http://www.jeepforum.com/forum/f177/92-xj-sadness-2075657/index2.html
uberxj92 is offline   Reply With Quote Quick reply to this message
Unread 08-31-2013, 11:39 PM   #33
Flyordie
Registered User
1985 XJ Cherokee 
 
Join Date: Dec 2009
Location: USA
Posts: 738
I did yes. Its got a dropped area right before the oil drain bolt.
Flyordie is offline   Reply With Quote Quick reply to this message
Unread 09-02-2013, 01:14 AM   #34
jeepdaddy2000
Registered User
1971 CJ5 
 
Join Date: Jan 2002
Location: Secret Squirrel hideout, afghanistan
Posts: 6,300
Quote:
I am well aware of how the oil system works in an internal combustion engine. Oil doesn't get 'lost', it gets circulated because the system is designed to continuously pump the oil to through the system, kind of like the cooling system.
Actually, the oil does get "lost", or forced from the bearing surfaces (preferably by oil pressure), where it drains back into the pan, to be recirculated by the pump again. This is different from a sealed system, in which the lube stays in the bearing (but you already stated that below......)

Quote:
Theoretically (that term has been used already) the engine could stay lubed with a closed pressurized system if the oil could stay cool and clean enough. That is too expensive to implement and hurts the oil dudes too much also.
The oiling system on a car is rudimentary. Maintain certain clearances and keep pumping oil through it
It is wildly impracticable to attempt to run a sealed pressurized system in a standard auto, and a non-pressurized (sealed bearing) system will not work for babbitt style bearings.


Quote:
Why would you want that high of a pressure???? HV pump is overkill especially on a 2.5. All that does is take hp away from the drivetrain and puts stress on the cam. Its a psych thing.
Again, do not confuse a high volume pump with a high pressure pump.

Higher pressure in a pump is achieved with a heavier bypass spring. This can be achieved with both a stock or high volume pump. Generally, there is little reason to run higher pressure on a standard engine, as all you're doing is putting a strain on your cam and distributor drive gears.

Higher volume is achieved with larger gears. A high volume pump will push more oil at the same pressure when compared to a stock pump. This is important when running engines that may see very low RPM's. While a stock pump may be running a constant 40LBS at idle (550 or so), it may drop drastically at 250-350RPM's. This may be a problem with engines that encounter moments of very low RPM's lugging over a technical obstacle. A high volume pump will be able to maintain volume (pressure) at these low speeds due to the added amount of oil it is trying to pack into the journals. Many HV pumps come with one or more pressure springs (my Melling came with three) offering a variety pressures.
On a worn engine, many times a high volume pump will compensate for excessive clearances by pushing more oil into the voids. A high pressure pump will not be effective at this until the gears rotate fast enough to create the volume necessary to overcome bleedoff (loss).
Contrary to what is being said, neither a high volume or a high pressure pump needs a larger pan. Neither of these pumps can move more oil than the engine clearances will allow, with the excess oil being route back into the pan via the bypass valve.
jeepdaddy2000 is offline   Reply With Quote Quick reply to this message
Unread 09-02-2013, 07:36 AM   #35
cruiser54
Web Wheeler
 
cruiser54's Avatar
1990 MJ Comanche 
 
Join Date: Oct 2009
Location: Prescott, Arizona
Posts: 10,318
Quote:
Originally Posted by uberxj92 View Post
So you're telling me that seals can withstand infinite amounts of pressure for infinite amounts of time?
Did you install the larger capacity pan?
The seals AREN'T under pressure except from the internal crankcase pressure air. No oil is pressure fed to seals on these engines.
The seals hold in "splashed" oil, not pressurized oil. That's why some of them have "slingers" right behind them on the crankshaft, to throw the splash away from them.
__________________
Quote:
Originally Posted by chris87xj View Post
If you own a Renix Jeep, you'll want to check this out. >

An index to over 25 write-ups can be found in Post #1.

Cruiser's Mostly Renix Tips
My Jeep Technical Photos

http://www.cherokeeforum.com/g/album/1725214
cruiser54 is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools






Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.